Ignition apparatus



Oct. 13, 1925- 155mm F. C. KROEGER IGNITION APPARATUS Filed Nov. 20, 1923 JEYUEHZ'UT' H5 fiEFIJE 5- Patented Oct. 13, 1925.

} UNITED STATES FREDERICK C. KBDMER, OI ANDERSON, INDIANA, ASSIG-NOB T0 GENERAL MOTORS PATENT OFFICE,

CORPORATION, A CORPORATION OF DELAWARE.

IGNITION APPARATUS.

Application filed Iovember 20, 1928. Serial No. 675,945.

To all whom it may concern:

Be it known that I, FREDERICK C. KROE- can, a citizen of the United State. of America, residing at Anderson, county of Madison, State of Indiana, have invented certain new and useful Improvements in Ignition Apparatus, of which the following is a full, clear, and exact description.

' This invention relates to cam operated periodic circuit breakers, such as ignition timers for internal-combustion engines, and has among its objects to simplify the con struction of such apparatus in-order to reduce the cost of manufacture. In order to obtain this object, the invention consists in providing strips of non-conducting material of the desired sectional contour and .dimensions, so constructed that rubbing blocks or cam followers can be readily formed simply by cutting off sections of the strip of nonconducting material.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings, wherein a preferred embodiment of one form of the present invention is clearly shown.

In the drawings:

F igs.. 1 and 2 are sectional and fragmentary plan views, respectively, of a strip of material from which the cam followers or rubbing blocks for a periodic circuit breaker can be constructed.

Fig.- 3 is a plan view of a circuit breaker or timer provided with a rubbing block made from material shown in Figs. 1 and 2.

Referring to Figs. 1 and 2, the strip of material 20 from which rubbing blocks may be constructed, is formed from layers of cloth 21 and a non-conducting material such as bakelite which can be formed or molded into a permanent shape. The strip of material is angular or L-shaped in cross-section; and rubbing blocks 23 cut from the strip 2O, along a line such as 22 at right angles to the length of the strip, will have legs24 and 2 5. The layers of cloth in one leg 24 are continuous with the layers of cloth in the leg 25. Each cloth layer 21 includes a substantially straight portion 26 inthe leg 24, and a straight portion 27 in the leg 25. The portions 26 and 27 afe joined by a curved portion 28, which, as regards the innermost layer of cloth, is rela- 31 carries tively gradual in curvature in order that the cloth fibers will not bebroken. This formation of the cloth layers is obtained by bending them over a suitably curved surface in the mold in which the layers are molded with the non-conducting material. The portion 29 of the rubbing block material, which does not include cloth, is composed of the right angles to the long dimensions of the strip 20. This arrangement is preferable because the number of warp threads generally exceed the number of weft threads in a piece of goods. The warp threads 30 extend, therefore, parallel to the legs of the rubbing block 23, and materially resist bendmg stresses at the apex of the block. The warp threads end in the end faces of the legs 24 and 25 asindicated by the dots 30 in Fig. 2. Therefore, the greater number of warp threads, the greater will be the reslstance to wear offered by these end faces.

As an example of a use tqwhich such rubbing block material is susceptible, a periodic circuit breaker or ignition timer is shown in Fig. 3 of the drawings. Support a stud 32 providing a pivotal mounting for a hub 33 to which one end of the strip of material, channel-shaped in section, is attached to provide a breaker lever 34. Lever 34 supports a movable contact 35 engaging a stationary contact 36 attached to an adjusting screw 37 threaded into a bracket 38 supported by the plate 31 but insulated therefrom. One le such as 25, of rubbing block 23 is attache to lever 34 by rivets 39, and the leg '24 cooperates with cam 40 attached to shaft 41 to cause themovement of lever 34 to separate contact 35 from contact 36. A spring 42 having one end engaging lever 34 and the other end coiled around a stud 43 and its intermediate portion coiled around the hub 33, causes the block 23 to engage the cam or the contact 35 to engage the contact 36. Due to the action of cam 40, the leg 24 of block 23 is subjected to bending stress which is greatest at the apex of the angle formed by the legs.

' disposed legs and including a This bending action is resisted .by the large number of warp threads which continue from one leg into the other. The action of the cam subjects the end face of leg 24 to wear, which is resisted to a large extent due to the presence of the relatively large number of warp threads which terminate in the end face of the leg 24.

While the form of embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted, all coming within the scope of the claims which follow.

What is claimed is as follows: 1. A cam rubbing block havin angularly liilurality of layers of cloth which extend into both legs,

thewarp threads of the cloth extending substantially parallel to the side faces of the egs.

2. A cam rubbing block having an ularly disposed legs and lncluding a plura ity of layers of cloth which extend into .both legs, the warp threads of the cloth extending substantially parallel to the side faces of the legs, and terminating in the end faces of the egs. I

3. A cam rubbing block having angularly disposed legs and including a plura ity of layers of woven cloth which extend throughout both legs, one set of threads of the cloth extending substantially perpendicular to the end faces of the legs.

In testimony whereof I hereto aflix my signature.

FREDERICK O. KROEGER 

